Composition for release layer of in-mold decoration

ABSTRACT

This invention relates to a composition suitable for the formation of a release layer in an in-mold decoration or thermal transfer printing process.

RELATED APPLICATION

This application claims the priority under 35 USC 119(e) of U.S.Provisional Application No. 60/564,018 filed on Apr. 20, 2004, thecontent of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTON

This invention relates to a composition suitable for the formation of arelease layer in an in-mold decoration or thermal transfer printingprocess.

BACKGROUND OF THE INVENTION

In-mold decoration processes involve decorating articles as they areformed, in mold, of a heated plastic material being injected into a moldcavity. Usually a tape or strip of a decorating or protective materialis automatically or manually advanced, pre-fed and positioned in themold cavity at each molding cycle, interfacing therein with the plasticmaterial as it is filled into the mold cavity, under heat and pressure.As the article is formed, the decorating material forms on the surfaceof the article and becomes an integral and permanent part of thearticle, through thermal transfer in the in-mold decoration process.Other molding processes such as thermal forming, blow molding andcompression molding or stamping may also be used for the transfer of adecorating or protective material. Sometimes the process may also becalled in-mold labeling or in-mold coating, and the transferableprotective material may be called a thermal transfer overcoat or durablecoat layer.

The decoration tape or strip usually comprises a carrier layer, arelease layer, a durable layer, an adhesive or tie-coat layer and also alayer of decorative designs (metal or ink). After the injection moldingtransfer, the carrier layer and the release layer are removed, leavingthe durable layer as the outmost layer. The release layer allows therelease of the carrier layer in a manner that minimizes damage to thedisplay panel and enables a fully automated roll transfer process duringmolding. The durable layer serves as a layer to protect the decorativedesigns and also the molded article. To improve the conformationproperties of the durable layer during injection molding of complicatedthree-dimensional parts, a UV curable durable layer is typically used.

U.S. Pat. No. 5,993,588 discloses a protecting layer (i.e., the durablelayer) formed from a heat and radiation curable resin composition whichcomprises a polyfunctional isocyanate and a polymer having a (meth)acrylequivalent weight from 100 to 300 g/eq., a hydroxyl value from 20 to 500and a weight average molecular weight from 5,000 to 50,000. The documentalso discloses that the durable layer may contain a UV absorber toimpart weather resistance to the protecting layer on the molded article.The UV absorber also reduces the photosensitivity of the durable layerand, to some degree, improves the room light handleability of thedecoration film during or before injection molding. Prematurecrosslinking of the durable layer in room light may occur duringcoating, printing, metal deposition, storage or handling of the tape orstrip. Suitable UV absorbers mentioned include salicylic acid-based,benzophenone-based, diphenyl acrylate-based, benzotriazole-based,triazine-based and amine-based UV absorbers.

However, incorporating a UV absorber into a durable layer (i.e.,protecting layer) formulation brings many tradeoffs. For example, itdecreases the efficiency of the photoinitiator in the composition due tocompetitive light absorption of the UV absorber. More photoinitiatorsmay be needed to compensate the loss of photosensitivity of thepost-molding UV curing step. Sometimes, the UV absorber may also cause ayellow or fluorescence tint of the protecting layer.

SUMMARY OF THE INVENTION

The first aspect of the invention is directed to a composition of arelease layer which comprises a copolymer or interpenetration network(IPN) formed from a composition comprising an amine-aldehyde condensateand a monomer or polymer comprising a moiety that is capable ofretarding, inhibiting or quenching radical polymerization orcrosslinking reaction.

The second aspect of the invention is directed to a composition of thefirst aspect of the invention which further comprises a UV absorbingmoiety.

The third aspect of the invention is directed to a composition of thefirst aspect of the invention which further comprises a silicone resin.

The fourth aspect of the invention is directed to a process for theformation of a release layer which process comprises dispersing ordissolving the release layer composition of the present invention in asolvent followed by curing said composition.

The release layer of the present invention has improved releasecharacteristics, adhesion properties, room-light handleability andshelf-life stability, without the tradeoff in photosensitivity in thepost-molding UV curing step.

The content of each document referred to in this application isincorporated by reference into this application in its entirety.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross section view of an in-mold decoration tape or strip.

FIG. 2 shows how the in-mold decoration tape or strip is fed into a moldcavity.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a cross-section view of an in-mold decoration tape or strip(10) which comprises a carrier layer (15), a release layer (11), adurable layer (12), a decorative design layer (13), and an adhesivelayer (14).

In an in-mold decoration process, the tape or strip (10) is fed into amold cavity (16) automatically or manually with the carrier layer (15)in contact with the mold surface as shown in FIG. 2. The tape or stripmay be thermally formed to a desirable shape before the feeding step.

The carrier (15) and adhesive (14) layers may be formed by methods knownin the art and all of the previously known carrier and adhesive layersmay be incorporated into the present invention.

For example, the carrier layer (15) usually is a thin plastic film witha thickness of from about 3.5 to about 100 microns, preferably about 10to about 50 microns. Polyethylene terephthalate (PET), polyethylenenaphthate (PEN) or polycarbonate (PC) film is particularly preferredbecause of their ready availability and thermomechanical stability.

The adhesive layer (14) is incorporated into the in-mold decoration tapeor strip to provide optimum adhesion of the decorative layer to the topsurface of the molded article. The adhesive layer may be formed from amaterial such as polyacrylate, polymethacrylate, polystyrene,polycarbonate, polyurethane, polyester, polyamide, epoxy resin, ethylenevinylacetate copolymers (EVA), butadiene rubber, thermoplastic elastomeror the like, or a copolymer, blend or composite thereof. Hot melt orheat activated adhesives such as polyacrylate, polyurethane or polyamideare preferred. Water based latexes such as polyurethane, acrylic andvinyl acrylic latexes or hybrid latexes thereof are also preferred. Thethickness of the adhesive layer may be in the range of about 1 to about20 microns, preferably in the range of about 2 to about 6 microns.

The decorative layer (13) may comprise an ink pattern and/or a metalliclayer formed from a method such as vapor deposition or sputtering,optionally followed by a patterning process. The ink pattern may beformed by a printing process such as gravure, flexo, screen, thermaltransfer or the like. Optionally, a tie layer may be used to enhance theadhesion between the durable layer and the decoration layer.

The durable layer (12) may be formed from any of the compositions knownin the art. For example, suitable materials for the durable layer mayinclude, but are not limited to, radiation curable multifunctionalacrylates (such as epoxy acrylates, polyurethane acrylates, polyesteracrylates, silicone acrylates, glycidyl acrylates), multifunctionalepoxides, multifunctional vinyl esters or ethers, diallyl phthalate andblends thereof.

Other suitable durable layer compositions are disclosed in U.S.Provisional Application No. 60/532,003, filed on Dec. 22, 2003; and U.S.Provisional Application No. 60/541,797, filed on Feb. 3, 2004; thecontents of both are incorporated herein by reference in their entirety.

The durable layer composition particularly suitable for the presentinvention may comprise a binder and a photopolymerizable material suchas a multifunctional acrylate, a multifunctional epoxide, amultifunctional vinyl such as multifunctional vinyl ether. The durablelayer may comprise a crosslinked network formed from the binder and acrosslinker such as a multifunctional isocyanate, multifunctionalthioisocyanate or multifunctional epoxide.

The durable layer of the decoration tape or strip may be partially orfully cured. If partially cured, a post curing step will be employedafter the molding and/or transferring step to enhance the durability,particularly hardness, chemical resistance and scratch resistance.

The durable layer may also comprise an additive such as thickener,surfactant, dispersant, UV stabilizer or antioxidant to control therheology, wettability, coating properties, weatherability and agingproperties. Fillers such as silica, Al₂O₃, TiO₂, CaCO₃, microcrystallinewax or polyethylene, Teflon or other lubricating particles may also beadded to improve, for example, scratch resistance and hardness of thedurable layer. The durable layer is usually about 2 to about 20 microns,preferably about 3 to about 8 microns in thickness.

The first aspect of the invention is directed to a composition for arelease layer which comprises a copolymer or interpenetration network(IPN) formed from a composition comprising (i) an amine-aldehydecondensate and (ii) a monomer or polymer comprising a moiety that iscapable of retarding, inhibiting or quenching radical polymerization orcrosslinking reaction. The component (ii), a monomer or polymercomprising a moiety that is capable of retarding, inhibiting orquenching radical polymerization or crosslinking reaction, ishereinafter referred to as a radical inhibitor or quencher for brevity.

Useful examples of the amine-aldehyde condensates may include, but arenot limited to, the formaldehyde condensates of a multifunctional aminesuch as melamine or urea.

The concentration of the amine-formaldehyde condensate in the driedrelease layer ranges from about 40% to about 95%, preferably from about50% to about 90% and more preferably about 60% to about 85%, by weight.

Examples of commercially available amine-aldehyde condensate may includeproducts by Cytec, such as Cymel® (melamine formaldyhyde), Melurac®(melamine urea formaldehyde) or Urac® (urea formaldehyde) and productsfrom Surface Specialty UCB, such as Resimene® (melamine-formaldehyde, HMor BM series or urea-formaldehyde, U series), Maprenal®(melamine-formaldehyde or benzoguanamine-formaldehyde), Viamin® (highlyreactive urea-formaldehyde with alkyl or nitrocellulose resin) orModacure® (highly reactive methylated melamine-formaldehyde modifiedstyrene allyl alcohol resin).

Useful radical inhibitors or quenchers may include, but are not limitedto, phenols, phenolic resins or precondensates thereof, oximes, hinderedamine oxides, nitrosobenzenes and oxidized derivatives or metalcomplexes thereof.

Suitable phenols and phenolic resins or precondensates thereof mayinclude, but are not limited to phenol, methoxyphenol, cresol, phenolformaldehyde resins, novolacs, resoles, resorcinol, salicylates,hydroxyl salicylates, trihydroxybenzene and analogs, derivatives oroxidized products thereof.

The phenolic resin or a precondensate thereof is usually heat treated oroxidized before, during or after the composition is coated onto thecarrier layer. The oxidized phenolic resin has a high extinctioncoefficient and can provide strong UV light absorbance even in a thinfilm of below or about 1 um.

Oxidation of the phenolic resin can be achieved thermally and/orphotochemically either in solution or in the form of dried coating. Asensitizer (such as isopropylthioxanthone or ITX) or catalyst (such asbenzoyl peroxide) may be used to improve the efficiency of photo orthermal oxidation in which the phenolic group is believed to be oxidizedto form a quinone derivative, which exhibits strong UV absorbance in therange of 300-500 nm.

Examples of commercially available phenol and phenolic resin includehydroquinone, methyl hydroquinone, alkylated phenols, Rutaphen® seriesof phenolic resins from Bakelite AG; GPRI®, BKS® and Arylzene series ofphenolic resins from Georgia-Pacific Resins, Inc.; Resicure®, HRJ® andSP® series of phenolic resins from Schenectady International Inc.,Arofene® (from Ashland), Phenodur® (resole type of phenolic resins) andSantolink® (such as EP 560, a solution of a butyl etherified phenolformaldehyde crosslinker resin).

Polyphenols prepared by enzymatic coupling as disclosed in, for example,U.S. Pat. No. 4,647,952 and U.S. Pat. No. 5,212,044, may also besuitable as the radical inhibitor or quencher in the composition.

Suitable hindered amine oxides may include, but are not limited to,TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy), 4-hydroxy TEMPO and4-oxo-TEMPO.

The radical inhibitor or quencher may take up about 1% to about 60%,preferably about 5% to about 50%, by weight of the dried release layer.

The presence of the radical inhibitor or quencher inhibits or quenchesthe undesirable radical reaction at the interface between the releaseand a radically curable durable layer before the release layer ispeeled-off during or after injection molding. The presence of a covalentbonded radical inhibitor or quencher in the release layer improves theproduct reliability, shelf-life and handle-ability of the resultingin-mold decoration film. When a phenolic inhibitor or quencher is used,the oxidation product of the phenolic compound may serve as an effectiveUV screening agent and further improves the storage stability and roomlight handleability of the durable layer coated thereon.

The release layer composition may further comprise a catalyst or acrosslinking agent for the condensation reaction.

Useful catalysts may include, but are not limited to, sulfiric acid,toluene sulfonic acid, dodecylsulfonic acid, dodecylbenzenesulfonicacid, hydrochloric acid, phosphoric acid, HBF₄, HPF₆, HSbF₆, HAsF₆ andthe salts thereof with a fugitive base such as ammonia or triethylamine.Preferred catalysts are toluenesulfonic acid or dedecylbenzenesulfonicacid. The concentration of the catalyst may range from about 0.1% toabout 5% and preferably about 1% to about 4%, by weight of the driedrelease layer.

Useful crosslinking agents may include, but are not limited to,formaldehyde, glyoxal, succinaldehyde, hexamethylene tetramine,phenolics, malonate blocked isocyanates, polyols, carbamatefunctionalized polymers, amine functionalized polymers and amidefunctionalized polymers. The concentration of the crosslinking agent, ifpresent, may range from about 0.1 to about 10% by weight and preferablyabout 1 to about 5%, by weight of the dried release layer.

The composition may further comprise a UV absorbing moiety. Useful UVabsorbing moieties may include, but are not limited to,o-hydroxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone,o-hydroxyphenyl-triazine, salicylates, α-cyano-β-phenyl-cinnamates,hydroxyphenyl benzotriazole and benzoxazinone. The UV absorbing moietymay be formed in-situ by oxidation thermally and/or photochemically ofthe radical inhibitor or quencher in the release layer composition.

Preferably the UV absorbing moiety does not absorb light at wavelengthsabove about 420 nm. The UV absorbing moiety may be self-crosslinking orreactive to other crosslinkable matrix to construct an interpenetrationnetwork (IPN) or a fully-crosslinked network. The concentration of theUV absorbing moiety, if present, may range from about 0.1 to about 20%,and preferably about 2 to about 10%, by weight of the dried releaselayer.

When the durable layer (12) composition comprises a multifunctionalacrylate and a multifunctional isocyanate or thioisocyanate, thephenolic moiety in the radical inhibitor or quencher in the releaselayer composition may react with the isocyanate or thioisocyanate in thedurable layer and such a reaction may introduce a certain amount ofadhesion between the durable layer and the release layer to avoiddelamination during handling and storage of the decoration tape orstrip. The linkage, urethane or thiourethane, formed between theisocyanate or thioisocyanate group from the durable layer and thephenolic moiety from the release layer, decomposes at a temperaturelower than 180° C., preferably lower than 150° C. and more preferablylower than 120° C. The thermal dissociation of the urethane orthiourethane linkage allows heat sensitive release property of therelease layer and reasonably good edge sharpness of the molded article.

The release layer composition of the present invention may furthercomprise a silicone resin. Suitable silicone resins may include, but arenot limited to, silicone block or graft copolymers or silicone polymershaving at least one reactive functional group. Examples of siliconeblock or graft copolymers include siloxane-poly(ethyleneglycol)-poly(propylene glycol) block copolymers or graft copolymers suchas Silwet silicones from OSi. Examples of silicone polymers having atleast one reactive functional group include those having at least onereactive functional group such as epoxy, isocyanate, hydroxyl, amide orthe like, in the main chain or side chains. Suitable main chains of thesilicone polymers may include polydialkylsiloxane and the like.

Silicone resins with reactive functional group can be reacted onto therelease layer before, during or after coating. Chemical bondings mayinclude, but are not limited to, urethane linkage which can be used tolink polydimethylsiloxane having hydroxyl functional groups with thephenolic resin in the release layer composition. The silicone resinhaving hydroxyl functional groups may also react with themelamine-formaldehyde condensate in the release layer composition to becrosslinked. The concentration of the silicone resin may range fromabout 0.1% to about 10% and preferably from about 1% to about 6%, byweight of the dried release layer.

The presence of a surface active silicone resin such as a Silwetsilicone surfactant also allows improvement of the coating quality andrelease/transfer properties of the decoration foil during injectionmolding, particularly in maintaining long term shelf life of releaseproperties after aging under high humidity and/or high temperatureconditions.

The release layer composition of the present invention may furthercomprise one or more of the following additives such as filler,surfactant, antifoamer or defoamer, thickener, binder or rheologymodifier.

Suitable fillers may include, but are not limited to, silica, CaCO₃,microgel particles, organic particles and mica. Its concentration, ifpresent, may range from about 0.5 to about 20% and preferably about 1 toabout 10%, by weight of the dried release layer.

Suitable surfactants may include, but are not limited to, Silwetsurfactants, poly(ethylene oxide-b-propylene oxide) such as Pluronicsurfactants from BASF and condensates of phenol and ethyleneoxide suchas Triton surfactants from Rohm & Haas. Its concentration, if present,may range from about 0.05 to about 5% and preferably about 0.1 to about3%, by weight of the dried release layer.

Suitable thickeners, binders or rheology modifiers may include, but arenot limited to, acrylic or methacrylic copolymers, acrylamidecopolymers, cellulose derivatives such as cellulose acetate butyrate orcellulose acetate propionate, poly(styrene-co-allyl alcohol),vinylpyrrolidone copolymers and the like. The thickners, binders orrheology modifiers may be either non-reactive or reactive to the releaselayer matrix. If present, the concentration of the thickner, binder orrheology modifier may take up about 1% to about 40% and preferably about5% to about 15%, by weight of the dried release layer.

The components of the release layer composition of the present inventionmay be dispersed or dissolved in a suitable solvent, such as ketones,esters, ethers, glycol ethers, glycolether esters, pyrrolidones, withketones and esters such as methyl ethyl ketone, (MEK), methyl propylketone (MPK), cyclohexanone, ethyl acetate, propyl acetate or butylacetate as the preferred. The release layer composition is coated, driedand cured on a carrier web substrate (such as PET).

In the formation of the in-mold decorative tape or strip (10), therelease layer (11), the durable layer (12), the decorative design layer(13) and the adhesive layer (14) are sequentially coated or laminatedonto the carrier layer (15). The coating may be accomplished by methodssuch as wire wound bar coating, slot coating, doctor blade coating,gravure coating, roll coating, comma coating, lip coating or the like orprinting methods such as gravure printing, screen printing or the like.

The release layer of the present invention may be thermally orphotochemically cured during or after the drying of the coating step.The thermal cure can be carried out at about 50° C. to about 120° C. forvarious lengths of time, for example, several minutes to hours,depending on the curing conditions and the composition. The durable,decoration and adhesive layers are then coated onto the release layerand they are transferred to the surface of the molded article by peelingoff the release layer and the carrier substrate during or afterinjection molding. The durable layer is now on the top of the moldedarticle and may be UV post cured using an UV conveyor at a speed of, forexample, 0.6 ft/min to 10 ft/min. The UV curing energy needed is usuallyin the range of from about 0.1 to about 5 J/cm², preferably about 0.3 toabout 1.2 J/cm².

The release layer of the present invention is suitable for all in-molddecoration processes for the manufacture of a plastic article. Suitablemolding processes for transferring of the decoration layer on therelease layer of the present invention may include, but are not limitedto, injection molding, compression molding, thermal forming, vacuumforming, blow molding or a combination of any two or more identified.

Examples of the material suitable for forming the molded article mayinclude, but are not limited to, thermoplastic materials such aspolystyrene, polyvinyl chloride, acrylics, polysulfone, polyarylester,polypropylene oxide, polyolefins, acrylonitrile-butadiene-styrenecopolymers (ABS), methacrylate-acrylonitrile-butadiene-styrenecopolymers (MABS), polycarbonate, polybutylene terephthalate (PBT),polyethylene terephthalate (PET), polyurethanes and other thermoplasticelastomers or blends thereof, and thermoset materials such ascompression molding or reaction injection molding grade polyurethanes,epoxy resin, unsaturated polyesters, vinylesters or composites, prepregsand blends thereof.

The article may be a plastic cover of a cell phone or pager. In fact,the release layer is useful for any plastic articles manufactured froman in-mold decoration process, such as personal accessories, toys oreducational devices, plastic cover of a personal digital assistant ore-book, credit or smart cards, identification or business cards, face ofan album, watch, clock, radio or camera, dashboard in an automobile,household items, laptop computer housings and carrying cases or frontcontrol panels of any consumer electronic equipments. This is clearlynot exhaustive. Other suitable plastic articles would be clear to aperson skilled in the art and therefore they are all encompassed withinthe scope of the present invention. The release layer of the presentinvention is also useful in applications such as the thermal transferprotective coating for thermal printing, inkjet printing and passportand other identification applications.

EXAMPLES

The following examples are given to enable those skilled in the art tomore clearly understand, and to practice, the present invention. Theyshould not be considered as limiting the scope of the invention, butmerely as being illustrative and representative thereof.

Example 1 UV Screening Efficiency

A. Formation of Film Comprising a Release Layer of the Present Invention

1.53 Grams of Durite SD-1708 (phenolic resin, Bordon Chemical, Inc.) wasdissolved in 7.2 gm of MEK. 1.3 Grams of CYMEL 303ULF (methylatedmelamine resin, Cytec Industries Inc), 0.03 gm of CYCAT 600 (DDBSA,dodecylbenzene sulfonic acid, a crosslinking catalyst, Cytec IndustriesInc.), 0.07 gm of DMS S12 (silanol terminated polydimethylsiloxane,Gelest Inc.) and 1.4 gm of CAB 553-04 (10% in MEK) (cellulose acetatebutyrate, Eastman Chemical Co.) were then added and mixed with aVortexer. The release layer composition formed was coated on a PET film(1.42 mil, PT1 from Mitsubishi, Interfilm Holding, Inc., Easley S.C.)with a #6.5 Meyer bar with a target thickness of about 2 um. The coatedfilm was dried at 70° C. for 5 minutes and cured at 120° C. for 10minutes.

The resultant film was then exposed to UV (Fusion V, H lamp at dosage of4.2 J/cm²) using a conveyor curing system.

A durable layer composition consisting of 7.67 gm (15% in MEK)CAB-553-0.4 (cellulose acetate butyrate, from Eastman Chemical Co.),2.94 gm (50% in MEK) of Ebecryl 1290 (aliphatic polyurethane acrylate,UCB Chemicals), 1.2 gm (30% in MEK) of MEK-ST (a silica dispersion fromNissan Chemicals), 0.40 gm of (25% in MEK) 1:1 w % ratio oftriethanolamine and poly-Q (aminated tetrol from Arch Chemicals,Norwalk, Conn.) and 0.43 gm of a photoinitiator (PI) solution containing1.5% of BMS (4-(p-tolylthio)benzophenone, Aldrich, Milwaukee, Wis.),0.8% of Irgacure 651 (2,2-dimethoxy-1,2-diphenylethane, Ciba SpecialityChemicals, Tarrytown, N.Y.), 0.15% of ITX (isopropyl thioxanthone,Aldrich, Milwaukee, Wis.), 0.2% of DBTDL (dibutyltin dilaurate, Aldrich,Milwaukee, Wis.), 0.1% of Irganox 1035 (thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], Ciba SpecialityChemicals, Tarrytown, N.Y.) and 0.2% of Tinuvin 123 [decanedioic acid,bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl)ester, reactionproducts with 1,1-dimethylethylhydroperoxide and octane from CibaSpeciality Chemicals, Tarrytown, N.Y.] in MEK was then overcoated ontothe cured release layer using a #28 Meyer bar with a target thickness ofabout 7 um and dried at 70° C. for 20 minutes.

The resultant film was then cured by UV exposure (Fusion D bulb, 0.8J/cm²) using a conveyor curing system from PET side with a step wedge.The photosensitivity reading on a 0.15 OD step wedge was 11.

B. Comparative Sample

The durable layer formed from the composition of Part B above was coatedon a PET film (1.5 mil) using a #28 Meyer bar with a target thickness ofabout 7 um and dried at 70° C. for 5 min. The resultant film was curedby UV exposure (Fusion D bulb, 0.8 J/cm²) using a Fusion conveyor curingsystem from PET side with a step wedge. The photosensitivity reading ona 0.15 OD step wedge was 13.

The UV photosensitivity of the durable layer was effectively retarded tobe half, based on the step wedge reading, due to the UV screening fromphenolic resin-modified release layer. In other words, UV protection ofthe durable layer was effectively increased 100% due to the presence ofthe release layer of the present invention.

Example 2 Thermal Sensitive Release & Edge Sharpness Improvement

The composition of the release layer of Example 1A was used in thisexample. A durable layer was prepared by pre-reaction of 6.84 gm (15% inMEK) of CAP-504-0.2 (cellulose acetate propionate, from Eastman ChemicalCo.) and 1.89 gm CaCO₃ (27.5% in MEK, containing 6.27% CAP-504-0.2) with2.53 gm (15% in MEK) of Desmodur N3300A (polyisocyanate, Bayer Polymers)and 0.1% DBTDL at 50° C. for 18 minutes. After pre-reaction, thefollowing ingredients were then added into the pre-reacted CAP solution:2.94 gm (50% in MEK) of Ebecryl 1290 (aliphatic polyurethane acrylate,UCB Chemicals), 0.1 gm of MEK-ST (30% in MEK, a silica dispersion fromNissan Chemicals), 0.40 gm of (25% in MEK) 1:1 w % ratio oftriethanolamine and poly-Q (aminated tetrol from Arch Chemicals,Norwalk, Conn.) and 0.43 gm of a photoinitiator (PI) solution containing1.5% of BMS (4-(p-tolylthio)benzophenone, Aldrich, Milwaukee, Wis.),0.8% of Irgacure 651 (2,2-dimethoxy-1,2-diphenylethane), 0.15% of ITX,0.2% of DBTDL, 0.1% of Irganox 1035 (thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]) and 0.2% ofTinuvin 123 [decanedioic acid,bis(2,2,6,6-tetramethyl-1-(octyloxy)-4-piperidinyl)ester, reactionproducts with 1,1-dimethylethylhydroperoxide and octane from CibaSpecialty Chemicals] in MEK. The resultant durable solution was thenovercoated onto the cured release layer using a #28 Meyer bar with atarget thickness of about 7 um and thermal cured at 70° C. for 20minutes.

An adhesive solution consisting of 46.24 gm of Sancure 2710 (aliphaticpolyurethane from Noveon Inc., Cleveland, Ohio), 2.01 gm of Bostex 361[butylated hydroxytoluene (BHT), Akron Dispersions, Akron, Ohio], 1.26gm of SOCAL 31 (precipitated calcium carbonate, Solvay Chemicals,Houston Tex.), 1.91 gm of EPOSTAR M30 (Benzoguanamine-formaldehydemicroparticle, Nippon Shokubai, Chiyoda-ku, Japan) and 48.58 gm ofde-ionized water was then overcoated onto the cured durable layer usinga #16 Meyer bar with a target thickness of about 3 um. The resultantfilm was inserted into an injection mold. A PMMA(polymethylmethacrylate) was injected into the mold cavity at 490° F.with the adhesive layer facing the plastic mixture. The durable layerand the adhesive layer were completely transferred to the molded plasticarticle after the release film was peeled off. The edge sharpness wasexcellent.

Example 3 Less Yellowness

The same compositions of Example 1A were used except that, in therelease layer, 1.53 gm of Resicure 5200 (meta-Novolac resin, ShenectadyInternational Inc.) was used to replace Durite SD-1708, 0.12 gm ofCYCAT600 was used to replace 0.03 gm of CYCAT and 3.06 gm of CAB 553-04(10% in MEK) was used to replace 1.4 gm of CAB 553-04. The same degreeof UV screening was observed with little yellowing in the visibleregion.

Example 4 Less Yellowness

The release layer composition of Example 3 was used except that, in therelease layer, 1.53 gm of SP12 (resoles resin, Shenectady InternationalInc.) was used to replace Resicure 5200. Very little yellowing wasobserved with almost the same degree of UV absorption at wavelength of350 nm. The hydroxyl groups on the resoles resin were crosslinked withthe melamine/formaldehyde matrix.

Examples 5-7 Use of Silicone-Alkyloxide Copolymers

The release layer composition of Example 3 was used except that 0.07 gmof Silwet 7280 (Example 5) or Silwet 7210 (Example 6) or Silwet 7657(Example 7) (Silwet is the trade name for polyethyleneoxide-polypropylene oxide-dimethylsiloxane copolymer, OSI) was used toreplace DMS-S12. The hydroxyl groups on the Silwet silicone resin werecrosslinked with the melamine/formaldehyde matrix.

Examples 8-10 Use of Combination of Silicone-Alkyloxide Copolymers

The release layer composition of Example 3 was used except thatdifferent combinations of alkyloxide-siloxane copolymers were used toreplace DMS-S12. In Example 8, a 4:1 ratio of Silwet L7657 and L7210 wasused. In Example 9, a 7:3 ratio of Silwet L7657 and L7210 was used. InExample 10, a 1:1 ratio of Silwet L7657 and L7210 was used. The examplesresulted release layers of different critical surface tensions anddifferent release forces between the release and durable layers.

Example 11 Use of 2,6-Bis(hydroxymethyl)-p-Cresol

The compositions in Example 1A were used except that, in the releaselayer, 4.6 gm of 2,6-bis(hydroxymethyl)-p-cresol (10% in ethylene glycoldimethyl ether) (Aldrich) was used to replace Durite SD-1708, 0.08 gm ofCYCAT600 was used to replace 0.03 gm of CYCAT 600 and 1.6 gm of CAB553-04 (10% in MEK) was used to replace 1.4 gm of CAB 553-04. 0.1 Gramof Silwet L7230 was used to replace 0.07 gm of DMS S12. The same degreeof UV screening was observed with little yellowing in the visibleregion.

Example 12 Reactive UV Absorber 2,2′-Dihydroxy-4-Methoxybenzophenone

The compositions of Example 1A were used except that, in the releaselayer, 0.6 gm of UVA 2,2′-dihydroxy-4-methoxybenzophenone (10% MEK)(from Aldrich) was used. 2.0 Grams of 2,6-bis(hydroxymethyl)-p-cresol(10% in ethylene glycol dimethyl ether) (Aldrich) was used to replaceDurite SD-1708, 0.08 gm of p-toluenesofonic acid (from Aldrich) was usedto replace 0.03 gm of CYCAT 600 and 1.6 gm of CAB 553-0.4 (10% in MEK)was used to replace 1.4 gm of CAB 553-04. 0.1 Gram of Silwet L7230 wasused to replace 0.07 gm of DMS S12. Much higher degree of UV screening(2 times UV screen of the release layer with only SP-12) was observedwith almost no observable yellowness in the visible region.

Example 13 Reactive UV Absorber 2-Hydroxy-1-Naphthaldehyde

The compositions of Example 1A were used except that, in the releaselayer, 0.6 gm of UVA 2-hydroxy-1-naphthaldehyde (10% MEK) (from Aldrich)was used. 2.0 Grams of 2,6-bis(hydroxymethyl)-p-cresol (10% in ethyleneglycol dimethyl ether) (Aldrich) was used to replace Durite SD-1708,0.08 gm of p-toluenesofonic acid was used to replace 0.03 gm of CYCAT600 and 1.6 gm of CAB 553-04 (10% in MEK) was used to replace 1.4 gm ofCAB 553-04. 0.1 Gram of Silwet L7230 was used to replace 0.07 gm of DMSS12. Much higher degree of UV screening (1.6 times of UV screen of therelease layer with only SP-12) was observed with less degree ofyellowing in the visible region.

Example 14 Pre-Reacted UV Absorber 2,2′-Dihydroxy-4-Methoxybenzophenone

The compositions in example 12 were used except UV absorber,2,2′-dihydroxy-4-methoxybenzophenone, was pre-reacted with2,6-bis(hydroxymethyl)-p-cresol before adding into the release layercomposition. The synthesis procedure was as follows.

0.5 Grams (2 mmole, Aldrich) of 2,2′-dihydroxy-4-methoxybenzophenone,0.16 gm of sodium hydroxide (4 mmole) and 40 mL of DI water were placedin a 100 mL round-bottomed flask fitted with a reflux condenser and acalcium guard tube. After the starting materials were dissolved, 0.51 gm(3 mmole, Aldrich) of 2,6-bis(hydroxymethyl)-p-cresol was added andrefluxed at 100° C. for 24 hours. The residual dark-colored liquid wascooled and acidified with 10% HCl. The resulting mixture was filtered,washed with water and dried in an oven. The residue was further purifiedby flash colum chromatography (10% ethyl acetate/hexane) to yield 0.3 gmof a pale yellow solid.

While the present invention has been described with reference to thespecific embodiments thereof, it should be understood by those skilledin the art that various changes may be made and equivalents may besubstituted without departing from the true spirit and scope of theinvention. In addition, many modifications may be made to adapt aparticular situation, materials, compositions, processes, process stepor steps, to the objective and scope of the present invention. All suchmodifications are intended to be within the scope of the claims appendedhereto.

1. A release layer composition for in-mold decoration which comprises acopolymer or interpenetration network formed from a compositioncomprising (i) an amine-aldehyde condensate; and (ii) a radicalinhibitor or quencher.
 2. The composition of claim 1 wherein saidamine-aldehyde condensate is a formaldehyde condensate of amultifunctional amine.
 3. The composition of claim 2 wherein saidmultifunctional amine is melamine or urea.
 4. The composition of claim 1wherein said amine-formaldehyde condensate in the dried release layerranges from about 40% to about 95% by weight.
 5. The composition ofclaim 1 wherein said radical inhibitor or quencher is selected from thegroup consisting of phenols, phenolic resins or precondensates thereof,oximes, hindered amine oxides, nitrosobenzenes and oxidized derivativesor metal complexes thereof.
 6. The composition of claim 5 wherein saidphenol and phenolic resin or a precondensate thereof is selected fromthe group consisting of phenol, methoxyphenol, cresol, phenolformaldehyde resins, novolacs, resoles, resorcinol, salicylates,hydroxyl salicylates, trihydroxybenzene and analogs, derivatives oroxidized products thereof.
 7. The composition of claim 1 wherein saidradical inhibitor or quencher is a polyphenol.
 8. The composition ofclaim 5 wherein said hindered amine oxide is TEMPO(2,2,6,6-tetramethyl-1-piperidinyloxy), 4-hydroxy TEMPO or 4-oxo-TEMPO.9. The composition of claim 1 wherein said radical inhibitor or quencherin the dried release layer ranges about 1% to about 60% by weight. 10.The composition of claim 1 further comprising a catalyst.
 11. Thecomposition of claim 10 wherein said catalyst is sulfiric acid, toluenesulfonic acid, dodecylsulfonic acid, dodecylbenzenesulfonic acid,hydrochloric acid, phosphoric acid, HBF₄, HPF₆, HSbF₆, HAsF₆ or a saltthereof with a fugitive base.
 12. The composition of claim 1 furthercomprising a crosslinking agent.
 13. The composition of claim 12 whereinsaid crosslinking agent is formaldehyde, glyoxal, succinaldehyde,hexamethylene tetramine, phenolics, malonate blocked isocyanates,polyols, carbamate functionalized polymers, amine functionalizedpolymers or amide functionalized polymers.
 14. The composition of claim1 further comprising a UV absorbing moiety.
 15. The composition of claim14 wherein said UV absorbing moiety is o-hydroxy benzophenone,2,2′-dihydroxy-4-methoxybenzophenone, o-hydroxyphenyl-triazine,salicylates, α-cyano-β-phenyl-cinnamates, hydroxyphenyl benzotriazole orbenzoxazinone.
 16. The composition of claim 1 further comprising asilicone resin.
 17. The composition of claim 16 wherein said siliconeresin is a silicone block or graft copolymer or a silicone polymerhaving at least one reactive functional group.
 18. The composition ofclaim 1 further comprising an additive.
 19. The composition of claim 1which is dispersed or dissolved in a solvent.
 20. The composition ofclaim 19 wherein said solvent is selected from the group consisting ofketones, esters, ethers, glycol ethers, glycolether esters, andpyrrolidones.
 21. A release layer for in-mold decoration which comprisesa copolymer or IPN formed from a composition comprising (i) anamine-aldehyde condensate, and (ii) a radical inhibitor or quencher. 22.The release layer of claim 21 wherein said composition furthercomprising one or more of the following: a catalyst, a crosslinkingagent, a UV absorbing moiety, a silicone resin or an additive.
 23. Aplastic article having a release layer formed from a compositioncomprising (i) an amine-aldehyde condensate, and (ii) a radicalinhibitor or quencher.
 24. The article of claim 23 which is a plasticcover of a cell phone or pager, a personal accessory, toy or educationaldevice, plastic cover of a personal digital assistant or e-book, creditor smart card, identification or business card, face of an album, watch,clock, radio or camera, dashboard in an automobile, household item,laptop computer housing or carrying case, front control panel of aconsumer electronic equipment, a thermal transfer protective coating ofidentification, passport, inkjet printed or thermal printed image.
 25. Adecorative tape or strip for in-mold decoration, which tape or stripcomprises a) a carrier layer; b) a release layer formed from acomposition comprising (i) an amine-aldehyde condensate, and (ii) aradical inhibitor or quencher; c) a durable layer; d) a decorativelayer; and e) an adhesive layer.
 26. The decorative tape or strip ofclaim 25 wherein said decorative layer is a metallic layer or an inklayer.
 27. A process for the formation of a release layer, which processcomprises: dispersing or dissolving a composition comprising (i) anamine-aldehyde condensate and (ii) a radical inhibitor or quencher and asolvent; and curing said composition.
 28. The process of claim 27further comprising a thermal or photo-oxidation step to oxidize theradical inhibitor or quencher to improve the UV screening efficiency ofthe release layer.